Author Topic: Problems in newly created Dark Masters  (Read 543 times)

Offline jkmorse

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Problems in newly created Dark Masters
« on: 2018 February 05 16:01:25 »
Juan et al.,

Up until 2 years ago I had issues with the way MaximDL writes FITS files.  The problem was that it often truncated the image to only 32,000 bits instead of the normal 65,000; thereby trashing all of the higher end signal.  By working out the exact settings in MaximDL to avoid the problem, it went away. 

But lately it’s made a comeback of sorts.  RGB images are fine, so far, I am guessing because they have stars that fall into the upper range even before stretching.  But my narrowband images are a mess.  I can do a work around since the issue materializes when I calibrate my subs so if I skip calibration I can still use the files, but that is not ideal.

I have tracked the problem to some newly created master darks.  Something in the way PI is writing the master darks under 1.8.5 (at least since mid-January when I took the darksubs and made the masterdark) is reintroducing the problem.  Attached is a file including everything you should need to test the problem, including new and old master darks, other calibration frames, and new darksubs, as well as a set of 18 OIII subs:

https://www.dropbox.com/sh/q1bum458ba460tk/AABAlbPbOh03cRQU2xhWThJfa?dl=0

I am using the latest version of PI for Windows and an up to date Windows 10 computer.  Let me know if you need anything else.

Thanks,

Jim
Really, are clear skies, low wind and no moon that much to ask for? 

New Mexico Skies Observatory
FLI Microline 16803
Planewave CDK17 - Paramount MEII
Planewave IFR90 - Astrodon LRGB & NB filters
SkyX - MaximDL - ACP

http://www.jimmorse-astronomy.com
http://www.astrobin.com/users/JimMors

Offline Juan Conejero

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Re: Problems in newly created Dark Masters
« Reply #1 on: 2018 February 06 10:32:49 »
Hi Jim,

Nothing has changed in PixInsight (publicly) for many months, so if there is a problem with the way these files are being generated, it shouldn't be our fault! On the other way, from a pure data loading/decoding perspective, there are no differences between raw broadband and narrowband frames: both are loaded and decoded as two-dimensional arrays of unsigned 16-bit integers.

I'll try to download and check out these files, but I'd guess the problem is in the original FITS files and their corresponding acquisition settings.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline jkmorse

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Re: Problems in newly created Dark Masters
« Reply #2 on: 2018 February 08 12:02:25 »
Thanks Juan.  Its just strange that my 2016 Dark works fine but the new 2018 dark is a bust.
Really, are clear skies, low wind and no moon that much to ask for? 

New Mexico Skies Observatory
FLI Microline 16803
Planewave CDK17 - Paramount MEII
Planewave IFR90 - Astrodon LRGB & NB filters
SkyX - MaximDL - ACP

http://www.jimmorse-astronomy.com
http://www.astrobin.com/users/JimMors